Cobra Voice Activity Detection
Web API

API Reference for the Cobra Web SDK (npm).

Cobra

class Cobra {}

Class for the Cobra VAD engine.

Cobra.create()

static async function create(
    accessKey: string,
    voiceProbabilityCallback: (voiceProbability: number) => void,
    options: CobraOptions = {}
): Promise<Cobra>

Creates an instance of the Cobra voice activity detection (VAD) engine.

Parameters

• accessKey string : AccessKey obtained from Picovoice Console.
• voiceProbabilityCallback (voiceProbability: number) => void : User-defined callback invoked when a frame of audio is processed. The callback provides a single parameter 'voiceProbability': a floating-point number within [0, 1].
• options CobraOptions : Optional configuration arguments.

Returns

• Cobra : An instance of the Cobra engine.

Cobra.process()

async function process(pcm: Int16Array): Promise<void>

Processes a frame of audio. The required sample rate can be retrieved from 'sampleRate' and the length of frame (number of audio samples per frame) can be retrieved from 'frameLength'. The audio must be single-channel and 16-bit linearly-encoded.

The voice probability result will be supplied via the voiceProbabilityCallback that was passed into Cobra.create().

Parameters

• pcm Int16Array : A frame of audio samples.

Cobra.release()

async function release(): Promise<void>

Releases resources acquired by the Cobra Web SDK.

Cobra.frameLength

get framelength(): number

Number of audio samples per frame.

Cobra.sampleRate

get sampleRate(): number

Audio sample rate accepted by Cobra.

Cobra.version

get version(): string

Cobra version string.

CobraOptions

type CheetahOptions = {
  processErrorCallback?: (error: string) => void
}

Cobra options type.

• processErrorCallback boolean : User-defined callback invoked if any error happens while processing the audio stream. Its only input argument is the error message. NOTE: This is only used by CobraWorker.

CobraWorker

class CobraWorker {}

A class for running the Cobra VAD engine as a web worker thread.

CobraWorker.create()

static async function create(
    accessKey: string,
    voiceProbabilityCallback: (voiceProbability: number) => void,
    options: CobraOptions = {}
  ): Promise<CobraWorker>

Creates an instance of CobraWorker.

Parameters

• accessKey string : AccessKey obtained from Picovoice Console.
• voiceProbabilityCallback (voiceProbability: number) => void : User-defined callback invoked when a frame of audio is processed. The callback provides a single parameter 'voiceProbability': a floating-point number within [0, 1].
• options CobraOptions : Optional configuration arguments.

Returns

• CobraWorker : An instance of CobraWorker.

CobraWorker.process()

async function process(pcm: Int16Array): void

Processes a frame of audio. The required sample rate can be retrieved from 'sampleRate' and the length of frame (number of audio samples per frame) can be retrieved from 'frameLength'. The audio must be single-channel and 16-bit linearly-encoded.

The voice probability result will be supplied via the voiceProbabilityCallback that was passed into CobraWorker.create().

Parameters

• pcm Int16Array : A frame of audio samples.

CobraWorker.release()

async function release(): Promise<void>

Releases resources acquired by the Cobra Web SDK.

CobraWorker.terminate()

async function terminate(): Promise<void>

Force terminates the instance of CobraWorker.

CobraWorker.frameLength

get frameLength(): number

Number of audio samples per frame.

CobraWorker.sampleRate

get sampleRate(): number

Audio sample rate accepted by Cobra.

CobraWorker.version

get version(): string

Cobra version string.

CobraError

class CobraError extends Error { }

Error thrown if an error occurs within Cobra VAD engine.

Errors:

class CobraActivationError           extends CobraError { }
class CobraActivationLimitError      extends CobraError { }
class CobraActivationRefusedError    extends CobraError { }
class CobraActivationThrottledError  extends CobraError { }
class CobraIOError                   extends CobraError { }
class CobraInvalidArgumentError      extends CobraError { }
class CobraInvalidStateError         extends CobraError { }
class CobraKeyError                  extends CobraError { }
class CobraMemoryError               extends CobraError { }
class CobraRuntimeError              extends CobraError { }
class CobraStopIterationError        extends CobraError { }